/Engine/Source/Runtime/Engine/Public/GPUSortManager.h
Callback that needs to be called in the rendering loop, after calls toFFXSystemInterface::PostRenderOpaque()are issued. Tasks with EGPUSortFlags::KeyGenAfterPostRenderOpaque get their client callbacks issued to set the initial keys and values. After this any sort task that hasn't been processed yet, inOnPreRender(), gets processed now.
void OnPostRenderOpaque ( class [FRDGBuilder](API\Runtime\RenderCore\FRDGBuilder) & GraphBuilder )